1. Field of the Invention
The present invention relates to a cellular wireless communication system. More particularly, the present invention relates to a method of controlling interference between different cells in a Time-Division Duplex (TDD) communication system for supporting a flexible subframe and a method of transmitting channel information by a terminal when an evolved Node B (eNodeB) schedules data through the flexible subframe.
2. Description of the Related Art
In recent years, an Orthogonal Frequency Division Multiple Access (OFDMA) scheme or a Single Carrier-Frequency Division Multiple Access (SC-FDMA) scheme similar thereto has been used as a scheme for transmitting high speed data through a wireless channel. The foregoing multiple access scheme allots and operates time-frequency resources that carry data or control information for each user in a non-overlapping manner, namely, to achieve orthogonality of the data or control information of each user.
An important consideration is support of a scalable bandwidth to provide high speed wireless data service in a cellular wireless communication system. As an example, a Long Term Evolution (LTE) system may have various bandwidths such as 20/15/10/5/3/1.4 MHz. Service providers may select one from among the foregoing bandwidths to provide service. There may be a plurality of types of terminals including a type supporting a maximum of up to 20 MHz of bandwidth and a minimum as small as 1.4 MHz of bandwidth. An LTE-Advanced (LTE-A) system, which is aimed at providing service that meets an International Mobile Telecommunications (IMT)-Advanced requirement, may provide a wideband service up to a maximum of 100 MHz of bandwidth by using LTE Carrier Aggregation (CA).
The LTE-A system uses a wider band than the LTE system for transmitting high speed data. Also, because backward compatibility with respect to LTE terminals is important, LTE terminals may access the LTE-A system to receive a service. To do this, the LTE-A system divides a total system band into sub-bands or Component Carriers (CCs) of a bandwidth capable of transmitting or receiving by an LTE terminal, combines a predetermined CC, and generates and transmits data for each CC to support high speed data transmission of the LTE-A system for each CC using a transmission/reception process of the LTE system. The CC may also be referred to as a cell. Each CC (or cell) is divided into a Primary Cell (PCell) and a Secondary Cell (SCell) in an application or importance in an aspect of a terminal. In an aspect of a terminal, the primary cell is one cell, and the secondary cell is any remaining cell except for the primary cell. In the LTE-A system, an uplink control channel may be transmitted in only the primary cell and an uplink data channel may be transmitted in the primary cell and the secondary cell.
Scheduling information with respect to data to be transmitted for each CC is reported to a terminal as Downlink Control Information (DCI). The DCI defines various formats to apply and operate a determined DCI format according to which it is scheduling information with respect to uplink data, scheduling information with respect to downlink data, a compact DCI, a DCI for power control, or spatial multiplexing using a multiple antenna. For example, a DCI format 1 being control information with respect to downlink data not applying a Multiple Input Multiple Output (MIMO) antenna is composed of control information as one or more as follows.                Resource allocation type 0/1 flag: notifies whether a resource allotment type is type 0 or type 1. Type 0 applies a bitmap type to allot a resource for each Resource Block Group (RBG). A fundamental unit of scheduling in LTE and LTE-A systems is a Resource Block (RB) expressed as time and frequency region resources. The RBG is configured by a plurality of RBs and becomes a fundamental unit of scheduling in type 0. Type 1 allots a certain RB in the RBG.        Resource block assignment: notifies of a RB allotted in data transmission. A resource expressed according to system bandwidth and resource allotment type is determined.        Modulation and coding scheme: notifies a modulation schemed and coding rate used in data transmission.        Hybrid Automatic Repeat Request (HARQ) process number: notifies a process number of HARQ.        New data indicator: notifies whether it is an HARQ initial transmission or a retransmission.        Redundancy version: notifies a redundancy version of an HARQ.        Transmission Power Control (TPC) command for Physical Uplink Control Channel (PUCCH): notifies a power control command with respect to a PUCCH being an uplink control channel.        
The DCI is transmitted through a Physical Downlink Control Channel (PDCCH) being a downlink physical control channel via a channel coding and modulation procedure.
However, there is a problem in that interference between cells in the forgoing wireless communication system occurs. That is, a signal between an evolved Node B (eNodeB) and a terminal in each cell acts as mutual interference to a terminal of an adjacent cell. Due to this, the performance of the wireless communication system is deteriorated.